4-Channel Mixer

Controls per Channel: Volume, Level Selector switch (Mic/Inst/Line)
Main Controls: Master Volume x1, Power switch
Connectors: Input x4, Output x1

Technical Specs

Input Level/ Input Impedance:
Mic: -50 dBm / 1.8 KOhms
Instrument: -35 dBm / 15 KOhms
Line: -20 dBm / 68 KOhms
Output Level:
Rated: +4 dBm
Maximum: +21 dBm
Output Load Impedance: More than 10 KOhms
Equivalent Input Noise: -115 dBm
Frequency Response: 10 Hz to 42 KHz
Crosstalke: 80 dB or more (between channels)
Power Consumption: 3W
Dimensions (WxDxH): 190 x 135 x 55 mm / 7 1/2 x 5 5/16 x 2 3/16 inch
Weight: 800 g / 1 lb 12 oz

http://www.synthmanuals.com/manuals/roland/bx-400/owners_manual/bx-400_om.pdf